Hi Glen,
great images, and thank you for the explanation! Often diatoms are to be found in one position in a slide, a couple in the sideways orientation and very few in between this makes it difficult to get a proper idea of the shape of the diatom.

Now there's a great big lurking "gotcha" in diatom study right there: keeping on your toes for the valve view vs. girdle view thing. If I had a dollar for every time I've been bamboozled by that one I could buy a new bottle of Pleurax.

Now there's a great big lurking "gotcha" in diatom study right there: keeping on your toes for the valve view vs. girdle view thing. If I had a dollar for every time I've been bamboozled by that one I could buy a new bottle of Pleurax. 8-)

In my defense there were a variety of diatoms on the sample slide ... still a rookie mistake though!

If it were possible to catch a small mass of such diatoms, and perform cleaning that preserves the valve, then at least the no of stria per 10um could be verified even with optical microscopy. This might help the ID. I have seen stalks of Limophoras on Ulva leaves, at my side of the Sea.